PEM Private Key Block

const re = new RegExp("-----BEGIN (?:RSA |EC |DSA |OPENSSH |ENCRYPTED |PGP )?PRIVATE KEY-----[\\s\\S]+?-----END (?:RSA |EC |DSA |OPENSSH |ENCRYPTED |PGP )?PRIVATE KEY-----", "g");
const input = "-----BEGIN RSA PRIVATE KEY-----\\nMIIEow...\\n-----END RSA PRIVATE KEY-----";
const matches = [...input.matchAll(re)];
console.log(matches.map(m => m[0]));

import re

pattern = re.compile(r"-----BEGIN (?:RSA |EC |DSA |OPENSSH |ENCRYPTED |PGP )?PRIVATE KEY-----[\s\S]+?-----END (?:RSA |EC |DSA |OPENSSH |ENCRYPTED |PGP )?PRIVATE KEY-----")
input_text = "-----BEGIN RSA PRIVATE KEY-----\nMIIEow...\n-----END RSA PRIVATE KEY-----"
for m in pattern.finditer(input_text):
    print(m.group(0))

package main

import (
	"fmt"
	"regexp"
)

func main() {
	re := regexp.MustCompile(`-----BEGIN (?:RSA |EC |DSA |OPENSSH |ENCRYPTED |PGP )?PRIVATE KEY-----[\s\S]+?-----END (?:RSA |EC |DSA |OPENSSH |ENCRYPTED |PGP )?PRIVATE KEY-----`)
	input := `-----BEGIN RSA PRIVATE KEY-----\nMIIEow...\n-----END RSA PRIVATE KEY-----`
	for _, match := range re.FindAllString(input, -1) {
		fmt.Println(match)
	}
}